Performance of superposition coding for downlink coordinated two-point system

In this correspondence, we consider a downlink coordinated two-point (DCTP) system, where two users communicate with two base stations. A superposition-coding (SC)-based transmission scheme is proposed to improve its error performance. A joint interference-cancellation and maximum-ratio-combining (IC-MRC) detection algorithm is proposed for the SC scheme, which reduces the error probability of the system compared with the classic SC (CSC) detector. Closed-form expressions of the bit error probability (BEP) of the proposed scheme are derived. Under the same power and time constraint, a signal-to-noise ratio (SNR) gain is obtained when the SC scheme is employed. Tight upper bounds of the BEP are derived to provide insight. Optimal power allocation is also derived to optimize the system performance in terms of the BEP.